Steam iron and valve structure

ABSTRACT

The invention discloses a steam iron wherein the usual control valve, regulating water flow from the water tank to the steam generating cavity, is of a non-metallic, low heat conductive material such as ceramic to eliminate the steam dome and result in better and faster steaming.

United States Patent Downing 1 July 11, 1972 [54] STEAM IRON AND VALVESTRUCTURE [72] Inventor: Arthur C. Downing, Ontario, Calif.

[73] Assignee: General Electric Company 221 Filed: Nov. 21, 1969 [21]Appl. No.: 878,840

[52] US. Cl ..38/77.83 [51] Int. Cl. ..D06t 75/06 [58] Field Search..38/77.5, 77.7, 77.83

[56] Relereuces Cited UNITED STATES PATENTS 3,218,742 11/1965 Carabet eta1. ..38/77.5

Denton v.38/7783 Tisdale et al ..38/77.83 X

Primary ExaminerPatrick D. Lawson Attorney-Lawrence R. Kempton, LeonardJ. Platt, John F. Cullen, Frank L. Neuhauser, Oscar B. Waddell andJoseph B. Forman ABSTRACT The invention discloses a steam iron whereinthe usual control valve, regulating water flow from the water tank tothe steam generating cavity, is of a non-metallic, low heat conductivematerial such as ceramic to eliminate the steam dome and result inbetter and faster steaming.

ZCMmSDruwingFlguns PATENTEDJUL H r972 Inventor Arthur C. Dowm r g bjgflL Qtwm g STEAM IRON AND VALVE STRUCTURE BACKGROUND OF THE INVENTION 1Field of the invention This invention is directed to a steam iron and,more particularly, to an improved control valve construction between thewater tank and steam generating cavity wherein the valve is preferably aceramic valve to reduce the number of parts needed and improve thesteaming performance of the iron.

2. Description of the prior art.

In most steam irons, steam is generated in a small cavity in thesoleplate and subsequently distributed under pressure to apertures inthe soleplate and to the fabric being ironed. In such irons, it iscustomary to support a water tank in a suitable manner within the ironand typically it is supported at its forward end by a steam dome that isgenerally made of stainless steel. The steam dome forms a part of aboiler coverplate that is secured to the soleplate and overlies andencloses soleplate cavities to form chambers where steam is generatedand distributed. A stainless steel steam dome is usually used to reduceheat transfer to the water tank so that the water does not boil withinthe tank when the iron is operating in a dry condition. Water flow fromthe tank into the steam generating cavity is through a small orifice ina brass valve body, with the valve body typically secured to the steamdome. Careful selection of the different metallic materials is requiredto avoid serious corrosion problems with the aluminum components in thepresence of moisture. Such corrosion changes the size of small orificesand corrosion flakes can clog the orifices resulting in poor or noperformance in the steaming position.

Such conventional structure uses several relatively costly components,such as a stainless steel dome and brass valve body. Further, the valvebody itself, when made of brass has generally been a costly machinedpart. Less expensive materials, such as aluminum, cannot be used with abrass tank because of corrosion problems.

The prior art construction has thus used several parts which can beimproved by a new design that performs the same function with fewer andcheaper parts and eliminates corrosion problems.

SUMMARY OF THE INVENTION Briefly described, the present invention isdirected to a steam iron that has a soleplate with a steam generatingcavity and a distributing cavity connected to steam discharge aperturesfor steaming operation. The iron has a water tank and a control valveassembly that regulates water flow from the tank to the generatingcavity. In this structure, the invention provides an improvement in thecontrol valve assembly regulating structure by supplying a coverplateover the cavities to form chambers with the soleplate. The control valvebody is formed of a non-metallic low heat conductive material, such as aceramic, that is disposed directly in the coverplate in an openingformed therein that is shaped to conform to a portion of the valve body.The valve body is provided with an exit that opens to extend toward orinto the generating cavity and it has an opposite entrance that ispreferably disposed directly in the bottom of the water tank. Suitablesealing means between the valve body and tank, and between the valvebody and coverplate provide liquid tight connections to permit thecomplete elimination of the steam dome. Thus, the main object of theinvention is an improved control valve assembly structure thateliminates one of the conventional elements to reduce cost andelimination of a corrosion problem as well as permitting the use of athicker, lower conducting and much stronger component by use of anon-metallic valve body.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation, partiallyin section and broken away, showing the location of the invention in aflat iron;

FIG. 2 is a partial sectional view of the improved cover-plate; and

FIG. 3 is an enlarged view of the individual valve body.

Referring to FIG. I, there is shown a typical flatiron of the type towhich this invention may be applied, comprising a smoothing member orsoleplate 10, a cover [2 enclosing various components within the iron,and an operating handle 14 molded from a thermal insulating material.Electric power may be supplied to the iron through a conventional cord,not shown, which enters the iron at the handle by means of a cord liftbushing 16. In order to adapt the iron for application to variousfabrics, a temperature selector 18 is provided adjacent the top forwardportion of handle 14 for convenience of the operator in selecting thedesired operating temperature. Also, the iron is provided with a pushbutton 20 or the equivalent which can be operated, for example, by anup-and-down motion to convert the iron from dry to steam operation orvice versa in a generally well-known manner.

Thermostatic switches for controlling operating temperatures of aflatiron are well-known in the art. In this particular embodiment, thetemperature responsive element is in the form of a bimetallic blade 22firmly secured to the flatiron soleplate 10 by means of a bolt 24. Suchbi-metallic blades, in a well-known manner, exhibit the characteristicof deforming or bending responsive to heat. In this particular instance,blade 22 is mounted so that it will bend or deform downwardly responsiveto increasing temperature of the soleplate. A compensating blade, notshown, is provided to even out the variations in temperature while theiron is coming up to steady state operating conditions as set byselector 18. The structure thus far described is conventional and isfully shown in US. Pat. No. 3,188,757 of common assignment.

The present invention is of particular importance with respect to itsapplication in a combination steam and dry iron in which steam isgenerated in a flash steam generating cavity formed in the soleplate. Atypical form of such a steam generating system includes a liquidreservoir in the form of a water tank 26 enclosed within cover 12 andwhich is supported in any suitable manner as will be described. Forsteam operation, the water in tank 26 is dripped through a control valveassembly, generally indicated at 28, into the steam generating cavity 30formed in the soleplate where it flashes into steam. Generated steam isdirected through a distribution cavity 32 which, in turn, is connectedto steam discharge apertures 34 in the soleplate to steam the fabricbeing ironed. The steam is confined by a coverplate 36 which overliesthe cavities to form chambers with the soleplate and thus confine thesteam and distribute it in a known manner.

In accordance with conventional practice prior to this invention, theconstruction has used a so-called steam dome between the water tank andsoleplate with the metallic control valve structure 28 located in thesteam dome. The steam dome has generally been stainless steel to reduceheat transfer to the liquid in tank 26 and prevent boiling of water inthe tank. Normally, this steam dome formed a part of the coverplate 36and the metallic valve structure 28 was disposed in this intermediatesteam dome structure as shown in the above referenced US. Pat. No.3,188,757.

In accordance with this invention, the control valve regulatingstructure has been improved by omitting the previously used intermediatesteam dome thus reducing the manufacturing cost. In addition, thisinvention provides a low cost replacement for the more costly machinedbrass valve body. The valve body made of brass in past constructionscould not be placed in direct contact with the aluminum cover plate 36because electrolytic corrosion attacks the aluminum with resultant badeffects on the small passages. Similarly, a brass valve body could notbe used with an aluminum tank, and an aluminum valve body has not beensatisfactory.

The valve body 38 according to this invention is formed of anon-metallic, low heat conductive material such as ceramic to bothreduce cost and prevent corrosion. Valve body 38, as seen in FIG. 3, isprovided with orifice 40 and water exit 42 at one end directed intogenerating cavity 30 and a water entrance 44 at the other end preferablydisposed directly in the bottom of tank 26 as seen in FIG. 1. The usualspring-biased valve stem 46 controls orifice 40 for steam or dryoperation as actuated by button 20.

In order to accommodate ceramic valve body 38, as seen in H0. 2,coverplate 36 is formed with an opening 48 therein that is shaped toconfon'n to a portion of the valve as seen in FIGS. 1 and 3 and thevalve is seated directly in opening 48 to extend toward the generatingcavity as shown in FIG. I. Suitable sealing means, such as siliconeelastomer gaskets 50, are used to seal the valve body between the tankand the coverplate and directly to each as shown.

Since the non-metallic and low heat conductive ceramic valve body isused, it is possible to use a thicker and thus stronger body with noadditional heat transfer and to dispense with the intennediate stainlesssteel dome. Thus, the water tank is directly connected to valve body 38and held down by a bracket 52 secured to the coverplate by screw 54. Thenonmetallic such as a ceramic valve body for the same wall thicknessprovides better thermal isolation than a metallic or stainless steeldome. At the same time, the non-metallic valve body can be used indirect proximity to the metal tank and metal coverplate without dangerof corrosion and regardless of the type of metal or alloy used in theother parts of the iron. Further, it should be noted that the phenomenondrifilm" which blocks water flow through a valve body when a filmprevents water from wetting the internal surface is not increased andindeed, may even be decreased, because a ceramic presents an easilywettable surface. Since the ceramic is a good insulator much thicker andthus stronger wall sections may be used without any additional heatbeing transmitted between the hot soleplate and the water tank. Further,the ceramic part is substantially lower in cost The present structurethus provides the necessary insulation between the parts, completelyeliminates the expensive steam dome, and eliminates corrosion to resultin better operating iron.

While there has been described a preferred form of the invention,obvious equivalent variations are possible in light of the aboveteachings. It is therefore to be understood that within the scope of theappended claims the invention may be practised, otherwise then asspecifically described, and the claims are intended to cover suchequivalent variations.

lclaim:

1. in a steam iron having a soleplate with a steam generating cavity anda distributing cavity connected to steam discharge apertures, a watertank and a control valve assembly regulating water flow from said tankto the generating cavity, the improvement in control valve regulatingstructure comprising;

a coverplate over said cavities to form chambers thereof with thesoleplate,

said control valve having a body formed of a ceramic material anddisposed directly in said coverplate,

said body having an exit at one end into said generating cavity and anentrance at the other end into said tank, and means sealing said valvebetween said tank and said coverplate.

2. Apparatus as described in claim 1 wherein said coverplate is formedwith an opening therein shaped to conform to a portion of said valvebody,

said valve being seated directly in said opening to extend toward saidgenerating cavity,

said entrance in the valve body being disposed in the bottom of saidtank, and

said sealing means sealing said valve directly to said tank and saidcoverplate.

k I I! l 1* a less costly and

1. In a steam iron having a soleplate with a steam generating cavity anda distributing cavity connected to steam discharge apertures, a watertank and a control valve assembly regulating water flow from said tankto the generating cavity, the improvement in control valve regulatingstructure comprising; a coverplate over said cavities to form chambersthereof with the soleplate, said control valve having a body formed of aceramic maTerial and disposed directly in said coverplate, said bodyhaving an exit at one end into said generating cavity and an entrance atthe other end into said tank, and means sealing said valve between saidtank and said coverplate.
 2. Apparatus as described in claim 1 whereinsaid coverplate is formed with an opening therein shaped to conform to aportion of said valve body, said valve being seated directly in saidopening to extend toward said generating cavity, said entrance in thevalve body being disposed in the bottom of said tank, and said sealingmeans sealing said valve directly to said tank and said coverplate.